Micro-Hardness and Compression Strength of Particle Sizes Recycling Aluminium Alloy AA6061 Using Powder Metallurgy Method

2017 ◽  
Vol 887 ◽  
pp. 74-82 ◽  
Author(s):  
Ahmed Sahib Mahdi ◽  
Mohammad Sukri Mustapa ◽  
Abdul Latif M. Tobi ◽  
Izzuddin Zaman
Keyword(s):  
Particle Size ◽  
Aluminum Alloy ◽  
Powder Metallurgy ◽  
Aluminium Alloy ◽  
Compression Strength ◽  
Volume Fraction ◽  
Current Paper ◽  
Powder Metallurgy Method ◽  
Particle Sizes ◽  
Micro Hardness

The micro-hardness and compression of recycling aluminum alloy AA6061 were investigated as a function of the different volume fraction and particle sizes by using powder metallurgy method. Three different groups of volume fraction and particle size were used 21.5, 50 and 78.5 % and 25,63 and 100 μm respectively. The current paper highlight on the effect of the various of particle size on the compression strength and microhardness results. The results of compression strength and micro-hardness show that the type of the higher amount of the smaller size was obtained for higher value for each of compression strength and micro-hardness 195.66 MPa and 79.796 Hv respectively.While it was the lower values on the type of the smaller amount of the smaller size (132.05 MPa and 50.369 Hv) respectively.

Effects of MgO Nano Particles on Microstructural and Mechanical Properties of Aluminum Matrix Composite prepared via Powder Metallurgy Route

2012 ◽  
Vol 05 ◽  
pp. 607-614 ◽  
Author(s):  
Mohammad Amin Baghchesara ◽  
Hossein Abdizadeh ◽  
Hamid Reza Baharvandi
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Powder Metallurgy ◽  
Volume Fraction ◽  
Average Particle Size ◽  
Aluminum Matrix ◽  
Nano Particles ◽  
Aluminum Matrix Composites ◽  
Average Particle ◽  
Powder Metallurgy Method

The objective of the present investigation was to evaluate the microstructural and mechanical properties of Al /nano MgO composite prepared via powder metallurgy method. Pure atomized aluminum powder with an average particle size of 1μm and MgO particulate with an average particle size between 60 to 80 nm were used. Composites containing 1.5, 2.5 and 5 percent of volume fraction of MgO were prepared by powder metallurgy method. The specimens were pressed by Cold Isostatic Press machine (CIP), subsequently were sintered at 575, 600 and 625°C. After sintering and preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of MgO particulates to aluminum matrix composites improves the mechanical properties.

Effect of Heat Treatment on Phase Transformation and Precipitation Behavior of Cu40Zn-1.0 Wt% Ti Brass via Powder Metallurgy

2011 ◽  
Vol 233-235 ◽  
pp. 2732-2735 ◽  
Author(s):  
Shu Feng Li ◽  
Hisashi Imai ◽  
Akimichi Kojima ◽  
Yoshiharu Kosaka ◽  
Koji Yamamoto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Powder Metallurgy ◽  
Solid Solubility ◽  
Chemical Potential ◽  
Volume Fraction ◽  
Powder Metallurgy Method ◽  
Micro Hardness ◽  
Precipitation Behavior ◽  
Β Phase

The effect of heat treatment on phase transformation, precipitation behavior and micro-hardness response of Cu40Zn-1.0Ti brass was investigated via powder metallurgy method. The volume fraction of α phase increased with elevated temperature, equaled to that of β phase at 400 °C, and reached to a maximum value of 55.9% at 500 °C. The solid solubility of Ti in Cu40Zn brass matrix decreased with elevated heat treatment temperature, showed high chemical potential for precipitates reaction in Cu40Zn brass. The micro-hardness of the BS40-1.0Ti brass was primarily dependent on the solid solubility of Ti, but also dependent on the phase ratio of α and β phase.

Observations of Precipitation Size and Fall Speed Characteristics within Coexisting Rain and Wet Snow

2006 ◽  
Vol 45 (10) ◽  
pp. 1450-1464 ◽  
Author(s):  
Sandra E. Yuter ◽  
David E. Kingsmill ◽  
Louisa B. Nance ◽  
Martin Löffler-Mang
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Volume Fraction ◽  
Bimodal Distribution ◽  
Particle Sizes ◽  
Large Standard Deviation ◽  
Air Temperatures ◽  
Isothermal Layer ◽  
Wet Snow ◽  
Fall Speed

Abstract Ground-based measurements of particle size and fall speed distributions using a Particle Size and Velocity (PARSIVEL) disdrometer are compared among samples obtained in mixed precipitation (rain and wet snow) and rain in the Oregon Cascade Mountains and in dry snow in the Rocky Mountains of Colorado. Coexisting rain and snow particles are distinguished using a classification method based on their size and fall speed properties. The bimodal distribution of the particles’ joint fall speed–size characteristics at air temperatures from 0.5° to 0°C suggests that wet-snow particles quickly make a transition to rain once melting has progressed sufficiently. As air temperatures increase to 1.5°C, the reduction in the number of very large aggregates with a diameter > 10 mm coincides with the appearance of rain particles larger than 6 mm. In this setting, very large raindrops appear to be the result of aggregrates melting with minimal breakup rather than formation by coalescence. In contrast to dry snow and rain, the fall speed for wet snow has a much weaker correlation between increasing size and increasing fall speed. Wet snow has a larger standard deviation of fall speed (120%–230% relative to dry snow) for a given particle size. The average fall speed for observed wet-snow particles with a diameter ≥ 2.4 mm is 2 m s−1 with a standard deviation of 0.8 m s−1. The large standard deviation is likely related to the coexistence of particles of similar physical size with different percentages of melting. These results suggest that different particle sizes are not required for aggregation since wet-snow particles of the same size can have different fall speeds. Given the large standard deviation of fall speeds in wet snow, the collision efficiency for wet snow is likely larger than that of dry snow. For particle sizes between 1 and 10 mm in diameter within mixed precipitation, rain constituted 1% of the particles by volume within the isothermal layer at 0°C and 4% of the particles by volume for the region just below the isothermal layer where air temperatures rise from 0° to 0.5°C. As air temperatures increased above 0.5°C, the relative proportions of rain versus snow particles shift dramatically and raindrops become dominant. The value of 0.5°C for the sharp transition in volume fraction from snow to rain is slightly lower than the range from 1.1° to 1.7°C often used in hydrological models.

Dry Sliding Wear Behavior of the Reinforced by Graphite Particle and Heat Treated of Recycled Aluminum AA6061 Based MMC Fabricated by Powder Metallurgy Method

2017 ◽  
Vol 740 ◽  
pp. 9-16
Author(s):  
Ahmed Sahib Mahdi ◽  
Mohammad Sukri Mustapa ◽  
Mahmod Abd Hakim Mohamad ◽  
Abdul Latif M. Tobi ◽  
Muhammad Irfan Ab Kadir ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Powder Metallurgy ◽  
Compression Strength ◽  
Sliding Wear ◽  
Wear Behavior ◽  
High Wear Resistance ◽  
Dry Sliding Wear ◽  
Powder Metallurgy Method ◽  
Heat Treated ◽  
Improvement Ratio

The micro-hardness and compression of recycling aluminum alloy AA6061 were investigated as a function of the different microstructure and constituent powder metallurgy method. Five specimens were selected to investigate the compression strength and microhardness. The first, as fabricated specimen (as compacted), the second was as heat treated by quenching and aging process. Three specimens were mixed with Graphite particles as a reinforcement material. Compression strength values were tested for the specimens as fabricated and heat treated which were 195 and 300 MPa, respectively. The improvement ratio was 52% for the specimen as heat treated. On the other hand, high wear resistance was given by the specimen as heat treated, whereas, the lower wear strength was at the specimen mixed with 4.5% Graphite. These results were attributed to that the wear resistance related to the microhardness value.

Oxygen-Enriched Combustion Characteristics of Lignite: A Case Study of the Pingzhuang Lignite from Inner Mongolia, China

2012 ◽  
Vol 550-553 ◽  
pp. 2868-2872
Author(s):  
Xiang Yun Chen ◽  
Yong Feng Zhang ◽  
Qian Cheng Zhang ◽  
Jie Bai ◽  
Fei Wu
Keyword(s):  
Particle Size ◽  
Oxygen Concentration ◽  
Volume Fraction ◽  
Particle Sizes ◽  
Temperature Zone ◽  
Thermogravimetric Method ◽  
Combustion Experiment ◽  
Lower Temperature ◽  
Lower Temperature Zone

Combustion curves of lignite samples from China in four different particle sizes and Oxygen-enriched condition were analyzed using non-isothermal thermogravimetric method. The lignite samples separated into -150+100 μm, -100+75 μm, -75+50 μm, and -50μm sizes. Combustion profiles shift to lower temperature zone as particle size decrease. Combustion profiles have little difference when the particle size below 100 μm in oxygen atmosphere; Oxygen-enriched combustion experiment were carried out in O2/N2 mixture atmospheres with the volume fraction of oxygen was 21%, 30%, 40%, 50%, 60% and 70%, respectively. As oxygen concentration increase profiles shift to lower temperature zone. and gets the proper range of oxygen concentration is about 50%.

Effect of the Matrix and Reinforcement Sizes on the Microstructure, the Physical and Mechanical Properties of Al-SiC Composites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
M. A. Salem ◽  
I. G. El-Batanony ◽  
M. Ghanem ◽  
Mohamed Ibrahim Abd ElAal
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Particle Sizes ◽  
Matrix Composites ◽  
Volume Fractions ◽  
The Matrix ◽  
Sic Composites ◽  
Sic Particle

Different Al-SiC metal matrix composites (MMCs) with a different matrix, reinforcement sizes, and volume fractions were fabricated using ball milling (BM) and powder metallurgy (PM) techniques. Al and Al-SiC composites with different volume fractions were milled for 120 h. Then, the Al and Al-SiC composites were pressed under 125 MPa and finally sintered at 450 °C. Moreover, microsize and combination between micro and nano sizes Al-SiC samples were prepared by the same way. The effect of the Al matrix, SiC reinforcement sizes and the SiC volume fraction on the microstructure evolution, physical and mechanical properties of the produced composites was investigated. The BM and powder metallurgy techniques followed by sintering produce fully dense Al-SiC composite samples with different matrix and reinforcement sizes. The SiC particle size was observed to have a higher effect on the thermal conductivity, electrical resistivity, and microhardness of the produced composites than that of the SiC volume fraction. The decreasing of the Al and SiC particle sizes and increasing of the SiC volume fraction deteriorate the physical properties. On the other hand, the microhardness was enhanced with the decreasing of the Al, SiC particle sizes and the increasing of the SiC volume fraction.

Microstructure and Properties of SiC Particle Reinforced Aluminum Matrix Composites by Powder Metallurgy Method

2013 ◽  
Vol 457-458 ◽  
pp. 131-134 ◽  
Author(s):  
Tao Fan ◽  
Cong Li Xiao ◽  
Yan Rong Sun ◽  
Hong Bo Li
Keyword(s):  
Particle Size ◽  
Wear Resistance ◽  
Powder Metallurgy ◽  
Sintering Temperature ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Average Particle ◽  
Particle Sizes ◽  
Matrix Composites ◽  
Sic Particle

The aim of this study is to investigate the effect of SiC particle pretreatment, aluminum matrix particle size and sintering temperature on relative density, hardness, microstructure and wear resistance to SiC particle einforced aluminum matrix composites. To this end, the amount of 16.7 wt.% SiC with average particle sizes 20μm was used along with pure aluminum of average particle size of 75 μm and 25μm. Powder metallurgy is a method used in the fabrication of this composite in which the powders were mixed using a planetary ball mill. By analyzing SEM micrograph and the Property test, it is concluded that SiC particle pretreatment has significant effect on the morphology of pecimens. pretreatment increase the interface adhesion, improve the wettability. SiC is uniformly distributed in the matrix, with good relation to the substrate, the maximum hardness is 51.1HB, the minimum wear rate is 0.1684%, while the density is 97.3%.For the same SiC content and particle size, the smaller the particle size of aluminum matrix is, the higher wear resistance of composite materials is on condition that others are same, the higher sintering temperature and the higher the wearability of composites, the wear resistance of the composite material is significantly improved after SiC pre-processing.The relative density increases with increasing aluminum matrix particle sizes under the same pressure and the holding time. The actual density of all samples reached the theoretical density over 96%, to a maximum of 98.9%.

Liquid Layering and the Enhanced Thermal Conductivity of Ar-Cu Nanofluids: A Molecular Dynamics Study

2016 ◽  
Author(s):  
Jithu Paul ◽  
A. K. Madhu ◽  
U. B. Jayadeep ◽  
C. B. Sobhan
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Particle Size ◽  
Molecular Dynamics Simulations ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Particle Sizes ◽  
Dynamics Simulations ◽  
Enhanced Thermal Conductivity ◽  
Liquid Layering

Nanofluids — colloidal suspensions of nanoparticles in base fluids — are known to possess superior thermal properties compared to the base fluids. Various theoretical models have been suggested to explain the often anomalous enhancement of these properties. Liquid layering around the nanoparticle is one of such reasons. The effect of the particle size on the extent of liquid layering around the nanoparticle has been investigated in the present study. Classical molecular dynamics simulations have been performed in the investigation, considering the case of a copper nanoparticle suspended in liquid argon. The results show a strong dependence of thickness of the liquid layer on the particle size, below a particle diameter of 4nm. To establish the role of liquid layering in the enhancement of thermal conductivity, simulations have been performed at constant volume fraction for different particle sizes using Green Kubo formalism. The thermal conductivity results show 100% enhancement at 3.34% volume fraction for particle size of 2nm. The results establish the dominant role played by liquid layering in the enhanced thermal conductivity of nanofluids at the low particle sizes used. Contrary to the previous findings, the molecular dynamics simulations also predict a strong dependence of the liquid layer thickness on the particle size in the case of small particles.

Discrete Element Modeling of Scraping Process and Quantification of Powder Bed Quality for SLM

2020 ◽  
Author(s):  
Kuldeep Mandloi ◽  
Parth Amrapurkar ◽  
Harish P. Cherukuri
Keyword(s):  
Particle Size ◽  
Volume Fraction ◽  
Numerical Models ◽  
Discrete Element ◽  
Contact Model ◽  
Powder Particle Size ◽  
Particle Sizes ◽  
Powder Bed ◽  
Size And Shape

Abstract In selective laser melting (SLM) and selective laser sintering (SLS) additive manufacturing techniques, the powder spreading process plays a key role in the quality of the manufactured parts. Some of the important parameters that influence the quality of the powder bed are the powder particle size distribution, spreader-type (roller or blade), spreader speed, size and shape of the particles. In this work, we use the discrete element method to study the effect of these parameters on the quality of the powder bed. The interactions between the particles is modeled using Hertz-Mindlin contact model as well as Hertz-Mindlin with JKR contact model with the latter being used for studies of the effect of cohesiveness of particles on powder bed quality. The Dynamic Repose Angle (DRA) is used for validating the numerical models. Our studies differ from the previous studies in that we have introduced quantitative measures for powder bed quality in the form of Discretized Volume Fraction (DVF) and Particle Flow Rate (PFR) for the layering process. With the help of these quantities, we studied various factors that affect powder bed quality: cohesiveness of the particles, spreader shape, particle size and shape, and the distribution of particle sizes. Our results indicate that as DVF and PFR decrease and DRA increases, the potential for cavities and shifting defects increases due to increase in cohesiveness. Use of fixed particle size in the simulations leads to higher DRA than when a normal distribution of particle sizes is considered. Our results show that the roller geometry provides better bed quality as compared to the blade type geometry.

Effect of Pore Forming Agent on Microstructures and Properties of Porous Molybdenum

2013 ◽  
Vol 761 ◽  
pp. 157-160
Author(s):  
Zhen Lin Lu ◽  
Xiao Jie Rao ◽  
Xiao Feng Xu
Keyword(s):  
Sodium Chloride ◽  
Powder Metallurgy ◽  
Influencing Factors ◽  
Fracture Strength ◽  
Volume Fraction ◽  
Transmission Rate ◽  
Powder Metallurgy Method ◽  
Compressive Fracture ◽  
Hydrogen Carbonate ◽  
Ammonium Hydrogen

The porous molybdenum was prepared by addition of pore forming agent and powder metallurgy method. The results show that the species and amount of pore forming agent are the primary influencing factors for the microstructures and properties of porous molybdenum. The pore shapes in porous molybdenum are regular and uniformly distributed. The porosity of porous molybdenum would be the largest and the transmission rate would be the best when sodium chloride was selected as pore forming agent. The compressive fracture strength of porous molybdenum would be more than 30MPa when the ammonium hydrogen carbonate was selected as pore formimg agent and its addition was 70 % (volume fraction). But the porosity would be the lowest.

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